Homenaje a una personalidad destacada de la Ingeniería Química argentina, el Ing. Miguel de Santiago

Cuando me pidieron que escribiera sobre el Ing. Miguel de Santiago, no lo dudé ni un momento, y consideré que era importante rendir homenaje a un pionero de la Ingeniería Química en Argentina y a un destacado y brillante egresado de la Universidad Nacional de La Plata (UNLP). El Ing. de Santiago tuvo una extensa trayectoria profesional como docente, investigador y funcionario. Recorreremos su biografía y los logros profesionales más importantes.Academia de la Ingeniería de la provincia de Buenos Aire

Resumen sobre el trabajo “Carne Argentina, Carne Sustentable: la ganadería no es parte del problema sino parte de la solución”, del IPCVA, parte 1

El Instituto de Promoción de la Carne Vacuna Argentina (IPCVA) presentó el 7 de septiembre de 2021 un estudio en el que 45 científicos argentinos relevan la situación actual de la sustentabilidad de la ganadería argentina para explicar cuál es el panorama actual y qué aspectos deben mejorarse. El trabajo se denomina “Carne Argentina, Carne Sustentable: la ganadería no es parte del problema sino parte de la solución”, que incluye temas tales como emisión de gases, huella hídrica, huella de carbono, cuidado ambiental y la sustentabilidad como atributo de calidad. Es un informe en el que han trabajado 45 científicos nacionales, coordinados por la Red de Seguridad Alimentaria del CONICET. Han sido coordinadores de los distintos ejes temáticos del trabajo, el Dr. Javier Echazarreta (INTI), el Ing. Agr. Ph. D. Aníbal Pordomingo (INTA), el Mag. en Economía, Roberto Bisang (UBA–CONICET) y el Ing. Agr. Ph. D. Ernesto Viglizzo (CONICET). A continuación se resumen y transcriben los conceptos más importantes del documento.Academia de la Ingeniería de la provincia de Buenos Aire

The Role of Water in the Cryopreservation of Seeds

Plant genetic resources are vitally important for human beings and the sustainability of the planet. Biodiversity conservation is the practice of protecting and preserving the abundance and variety of all species (Lambardi et al. 2004; Walters 2006). Neotropical ecosystems are submitted to constant pressure by human activity; in these ecosystems the number of plants at risk of genetic depletion or extinction and the loss of important genetic resources is continuously increasing. Preservation of plant biodiversity avoids the risk that species and plant varieties may become extinct, producing a definitive loss of their genetic variability. Preservation of plants only in field collections is risky, as valuable germplasm can be lost (genetic erosion) because of pests, diseases, and adverse weather conditions.Centro de Investigación y Desarrollo en Criotecnología de AlimentosFacultad de Ingenierí

Chemical Preservatives Action on Microbial Growth in a Model System of Refrigerated Prepeeled Potatoes

The effect of different concentrations of citric acid and ascorbic acid (applied individually or in mixture's) on microbial growth in potato homogenate was analyzed and compared to the sodium bisulfite action during storage at 4°C in low gaseous permeability films. These experiments allowed one to simulate the behavior of prepeeled potatoes but with a known amount of added preservative to evaluate additive or synergic effects. Total viable microorganisms, Enterobacteriaceae , Pseudomonas sp., Lactobacillus sp., molds, yeasts, Clostridium sulfite reducers, psychrotropic microorganisms, and aerobic and anaerobic viable spores were analyzed during storage time. Inhibition indexes produced by the tested preservatives were calculated for the different microorganisms. Sodium bisulfite solutions (100 ppm) had no inhibitory effect. Concentrations of 3,500 ppm citric acid and 10,000 ppm ascorbic acid showed antimicrobial action as well as mixtures of citric acid/ascorbic acid of the following compositions (in terms of total acids concentration): 2,700/2,000, 3,500/2,000, and 2,700/3,000 ppm. A higher effect on Enterobacteriaceae was observed in comparison with other microorganisms. The apparent synergic effect of these acids when they were applied together was demonstrated to be actually an additive effect when concentrations of undissociated acid in the mixtures were considered instead of total concentration.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Effect of the Addition of Proteins and Hydrocolloids on the Water Mobility in Gluten-Free Pasta Formulations

In a gluten free pasta formulation (suitable for celiac people), the influence of each constituent has a major importance on the final product quality, especially water and hydrocolloids contents used to replace the gluten matrix. The presence of hydrocolloids and proteins in dough may modify the availability of water to interact with starch in the gelatinization process. The aim of the present work was to investigate the effect of the addition proteins and hydrocolloids addition on the water-starch interaction using a triangular mixture design. Basic dough formula consisted in a mixture of corn starch and flour (4:1, 53.5%), 1%NaCl, and 3% sunflower oil, water (35.48-39.5%), gums (xanthan and locust bean gums, 2:1 ratio, 0.512-2.519%), and proteins (dry egg and ovoalbumin mixtures, 10:1 ratio, 0.683-6.704%) Combinations of gums, proteins, and water were used in a simplex-centroid design with constrains. Modulated differential scanning calorimetry was used to study starch gelatinization and the amount of unfrozen water in the samples; thermograms were obtained between -50ºC and 140ºC (heating rate 5ºC/min, modulated at ±1ºC, period of 60s). Regarding the process of gelatinization, a biphasic endotherm was observed; when the free water content of the dough was progressively reduced (0.94 to 0.42g H2O/ g dough), endotherms shifted to higher temperatures (onset from 56.7ºC to 63.1ºC, first peak from 75.1ºC to 77.6ºC) following a linear relationship. The response surface analysis of the unfrozen water content of the complex composite system as a function of the concentration of proteins, hydrocolloids, and water led to a “saddle” type surface, involving interactions between components.Facultad de Ciencias ExactasCentro de Investigación y Desarrollo en Criotecnología de AlimentosFacultad de Ingenierí

Response to Readers' Comments on Published Paper: "Ultraviolet Treatment of Orange Juice to Inactivate E. coli O157:H7 as Affected by Native Microflora" by Juan M. Oteiza, Leda Giannuzzi, Noemí Zaritzky : [Food and Bioprocess Technology 3-4 (2010) 603-614]: UV Irradiation Dose Corrections

In this paper, we described that for each assay, 5 ml of inoculated orange juice (with individual Escherichia coli O157:H7 strains or with the strain cocktail) was placed in sterile Petri dishes (9 cm in diameter) separately; thus, a layer of 0.7-mm thick was obtained; the distance between the sample and the UV lamp was fixed at 15 cm. A special UV chamber was designed with four UV germicidal, mercury low-pressure lamps (254 nm, UV, Lux 30 W/G30 T8, Philips), located on the top of the chamber. To analyze the effect of the stirring velocity, an orbital shaker with selectable speed was used. This velocity was set at 220 rpm. A ventilation system was included in the chamber to avoid warming of the samples. UV intensity flux or irradiance at 254 nm (I, expressed in milliwatts per square centimeter), exposures times (t, ranging between 0 and 10 min), and the radiation dose (energy, E=I×t, ranging between 0 and 2 J/cm²) were measured using a UV digital radiometer (Vilber Lourmat, model VLX-3 W CE; France).Centro de Investigación y Desarrollo en Criotecnología de Alimento

Application of multivariate statistical analysis to assess browning bsusceptibility in sweet potatoes (Ipomoea batatas (l.) Lam.) cultivars, based on chemical and enzymatic determinations

The selection of a sweet potato cultivar for minimal processing must be performed considering the nutritional value and the lower susceptibility to browning development, which will result in greater stability of the vegetable colour. The aim of this work was to evaluate browning susceptibility in four sections of two sweet potato cultivars combining chemical and enzymatic determinations with colour variables, by applying multivariate statistical techniques. Each cultivar had a characteristic browning pattern; in white cultivar colour changes were represented by changes in variable b* while in the red cultivar these changes responded to variations in variable a*.The regions with major colour changes (ΔE*>6) after 24 hours also had high levels of phenolic compounds (658±98 mg chlorogenic acid/kg fresh tissue) and high oxidative enzymes activities. Principal Component Analysis indicated that three regions in white cultivar and two in red cultivar had low browning susceptibility. Partial Least Square analysis indicated that colour changes (ΔE*) were highly associated with Polyphenoloxidase activity and phenolic compounds. By comparing both cultivars analyzed, the white cultivar presented 3 regions with low browning susceptibility and therefore would be more suitable for minimally processing. This low susceptibility would be related to low phenol content and lower enzyme activities.Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA)Facultad de Ciencias Agrarias y Forestales (FCAF

Application of multivariate statistical analysis to assess browning bsusceptibility in sweet potatoes (Ipomoea batatas (l.) Lam.) cultivars, based on chemical and enzymatic determinations

The selection of a sweet potato cultivar for minimal processing must be performed considering the nutritional value and the lower susceptibility to browning development, which will result in greater stability of the vegetable colour. The aim of this work was to evaluate browning susceptibility in four sections of two sweet potato cultivars combining chemical and enzymatic determinations with colour variables, by applying multivariate statistical techniques. Each cultivar had a characteristic browning pattern; in white cultivar colour changes were represented by changes in variable b* while in the red cultivar these changes responded to variations in variable a*.The regions with major colour changes (ΔE*>6) after 24 hours also had high levels of phenolic compounds (658±98 mg chlorogenic acid/kg fresh tissue) and high oxidative enzymes activities. Principal Component Analysis indicated that three regions in white cultivar and two in red cultivar had low browning susceptibility. Partial Least Square analysis indicated that colour changes (ΔE*) were highly associated with Polyphenoloxidase activity and phenolic compounds. By comparing both cultivars analyzed, the white cultivar presented 3 regions with low browning susceptibility and therefore would be more suitable for minimally processing. This low susceptibility would be related to low phenol content and lower enzyme activities.Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA)Facultad de Ciencias Agrarias y Forestales (FCAF

Effect of the Addition of Proteins and Hydrocolloids on the Water Mobility in Gluten-Free Pasta Formulations

In a gluten free pasta formulation (suitable for celiac people), the influence of each constituent has a major importance on the final product quality, especially water and hydrocolloids contents used to replace the gluten matrix. The presence of hydrocolloids and proteins in dough may modify the availability of water to interact with starch in the gelatinization process. The aim of the present work was to investigate the effect of the addition proteins and hydrocolloids addition on the water-starch interaction using a triangular mixture design. Basic dough formula consisted in a mixture of corn starch and flour (4:1, 53.5%), 1%NaCl, and 3% sunflower oil, water (35.48-39.5%), gums (xanthan and locust bean gums, 2:1 ratio, 0.512-2.519%), and proteins (dry egg and ovoalbumin mixtures, 10:1 ratio, 0.683-6.704%) Combinations of gums, proteins, and water were used in a simplex-centroid design with constrains. Modulated differential scanning calorimetry was used to study starch gelatinization and the amount of unfrozen water in the samples; thermograms were obtained between -50ºC and 140ºC (heating rate 5ºC/min, modulated at ±1ºC, period of 60s). Regarding the process of gelatinization, a biphasic endotherm was observed; when the free water content of the dough was progressively reduced (0.94 to 0.42g H2O/ g dough), endotherms shifted to higher temperatures (onset from 56.7ºC to 63.1ºC, first peak from 75.1ºC to 77.6ºC) following a linear relationship. The response surface analysis of the unfrozen water content of the complex composite system as a function of the concentration of proteins, hydrocolloids, and water led to a “saddle” type surface, involving interactions between components.Facultad de Ciencias ExactasCentro de Investigación y Desarrollo en Criotecnología de AlimentosFacultad de Ingenierí

Effect of the Addition of Proteins and Hydrocolloids on the Water Mobility in Gluten-Free Pasta Formulations

In a gluten free pasta formulation (suitable for celiac people), the influence of each constituent has a major importance on the final product quality, especially water and hydrocolloids contents used to replace the gluten matrix. The presence of hydrocolloids and proteins in dough may modify the availability of water to interact with starch in the gelatinization process. The aim of the present work was to investigate the effect of the addition proteins and hydrocolloids addition on the water-starch interaction using a triangular mixture design. Basic dough formula consisted in a mixture of corn starch and flour (4:1, 53.5%), 1%NaCl, and 3% sunflower oil, water (35.48-39.5%), gums (xanthan and locust bean gums, 2:1 ratio, 0.512-2.519%), and proteins (dry egg and ovoalbumin mixtures, 10:1 ratio, 0.683-6.704%) Combinations of gums, proteins, and water were used in a simplex-centroid design with constrains. Modulated differential scanning calorimetry was used to study starch gelatinization and the amount of unfrozen water in the samples; thermograms were obtained between -50ºC and 140ºC (heating rate 5ºC/min, modulated at ±1ºC, period of 60s). Regarding the process of gelatinization, a biphasic endotherm was observed; when the free water content of the dough was progressively reduced (0.94 to 0.42g H2O/ g dough), endotherms shifted to higher temperatures (onset from 56.7ºC to 63.1ºC, first peak from 75.1ºC to 77.6ºC) following a linear relationship. The response surface analysis of the unfrozen water content of the complex composite system as a function of the concentration of proteins, hydrocolloids, and water led to a “saddle” type surface, involving interactions between components.Facultad de Ciencias ExactasCentro de Investigación y Desarrollo en Criotecnología de AlimentosFacultad de Ingenierí